Wireless communications has been evolving toward ever increasing data rates (e.g., from IEEE 802.11a/g to IEEE 802.11n to IEEE 802.11ac). In high-density deployment situations, overall system efficiency may become more important than higher data rates. For example, in high-density hotspot and cellular offloading scenarios, many devices competing for the wireless medium may have low to moderate data rate requirements. The frame structure used for conventional and legacy IEEE 802.11 communications including legacy very-high throughput (VHT) communications may be less suitable for such high-density deployment situations.
One issue with these conventional communication techniques is that a preamble is sent for every packet transmission irrespective of which devices are communicating and when they last communicated with each other. This overhead becomes more significant in high-density deployment situations particularly for devices that have low to moderate data rate requirements.
Thus, there are general needs for devices and methods that improve overall system efficiency in wireless networks, particularly for high-density deployment situations. There are also general needs for devices and methods suitable for HEW communications. There are also general needs for devices and methods suitable for HEW communications that can coexist with legacy devices.